<?php
class db{
var $linkid;
var $sqlid;
var $record;
function db($host="",$username="",$password="",$database=""){
	if(!$this->linkid) @$this->linkid = mysql_connect($host, $username, $password) or die("连接服务器失败.");
	@mysql_select_db($database,$this->linkid) or die("无法打开数据库");
	return $this->linkid;
}

function query($sql){
	if($this->sqlid=mysql_query($sql,$this->linkid)) {
		return $this->sqlid;
	}else {
		$this->err_report($sql,mysql_error);
		return false;
	}
}

function nr($sql_id=""){
	if(!$sql_id){
		$sql_id=$this->sqlid;
	}
	return mysql_num_rows($sql_id);
}

function nf($sql_id=""){
	if(!$sql_id){
		$sql_id=$this->sqlid;	
	}
	return mysql_num_fields($sql_id);
}

function nextrecord($sql_id=""){
	if(!$sql_id){
		$sql_id=$this->sqlid;	
	}
	if($this->record=mysql_fetch_array($sql_id)){
		return $this->record;	
	}else{
		return false;	
	}
}

function f($name){
	if($this->record[$name]){
		return $this->record[$name];
	}else {
		return false;
	}
}

function close() {mysql_close($this->linkid);}

function lock($tblname,$op="WRITE"){
	if(mysql_query("lock tables ".$tblname." ".$op)){
		return true;
	}else{
		return false;
	}
}

function unlock(){
	if(mysql_query("unlock tables")){
		return true;	
	} else{
		return false;
	}
}

function ar() {
      return @mysql_affected_rows($this->linkid);
}

function i_id() {
    return mysql_insert_id();
}

function err_report($sql,$err)
{
	echo "Mysql查询错误<br>";
	echo "查询语句：".$sql."<br>";
	echo "错误信息：".$err;
}
}?>